In recent years, the use of liquefied natural gas (LNG) or liquefied petroleum gas (LPG) has rapidly expanded throughout the world.
In particular, LNG is environmentally friendly due to less emission of pollutants upon combustion and is increasingly used in various fields.
LNG is a colorless transparent liquid obtained by cooling natural gas mainly including methane to about −163° C. and has a volume of about 1/600 that of natural gas. Thus, natural gas is liquefied into LNG for efficient transportation and an LNG carrier is used for marine transportation of LNG.
With strengthened international and national regulations on ships, an interest on environmentally friendly high efficiency fuel for ships has also been increased. Among such fuel, a dual fuel (DF) engine capable of using boil-off gas obtained through natural or forced gasification of LNG is developed and used for ships.